An eight-month slump in the oil market has reached a bottom and prices will recover, Iraq’s oil minister predicted Tuesday.

Oil prices have slumped more than 50% since June amid a surge in oil supply led by U.S. shale oil production and sluggish demand. Iraq and other members of the Organization of the Petroleum Exporting Countries have taken a hands-off approach to the selloff, opting to defend market share rather than cut production...